Perhaps you should try some spelling variations:
closed chain » cold chain, closer than
gene closed » gene clone
yan wang » yuan wang, yang yang, qian wang
hua gene » human gene, a gene, hua ren
wong siu » wong shiu, kong siu, wong sau
ron paul » von paul, robyn paul, robin paul
nan yan » nan ya, wang yan, qian yan

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: nan yan wang hua gene closed chain ((wong siu) or (ron paul)) ;~.
• If you are trying to use Boolean operators, they must be ALL CAPS: nan yan wang hua gene closed chain ((wong siu) OR (ron paul)) ;.
• Adding a wildcard symbol may retrieve word variants: nan yan wang hua gene closed chain ((wong siu) or (ron paul)) ;*.